Several topics were studied in the interaction of intense laser pulses with dropletand cluster sources. Laser pulse-formatting that can enhance laser-to-EUV conversionefficiency in the 13.5nm band for next generation lithography was first explored,using droplet sources as the laser target. Xenon droplets size distribution wasmeasured, and the droplet plasma spectrum irradiated by various laser energies wasscanned. A 2-pulse heater setup and a 4-pulse stacker scheme were built and studied.Results suggest that, unlike droplets of argon (Ar) and krypton (Kr), the ionization-state distribution in xenon may be much more transient. The decay timescales for.